I would depend on a lot of things. A better way to estimate would be to first write a complete feature spec first. And then put it up on sites like ODesk and Elance and get contractors to bid on it.
You will get some very low ball offers but those aren't necessarily the right choice (they usually aren't). On ODesk, a decent programmer can run you around $20/hr. Go with ones that have established feedback and have put in 1000+ hours on the ODesk platform.
Another option is to get a technical co-founder (or even just an advisor) who can help fill in the gap -- and at least help you avoid pitfalls.